1. Technical Field
The present disclosure relates to the field of avalanche diodes, which are especially used as protection diodes in integrated circuits.
2. Discussion of the Art
One of the current ways of obtaining a determined reference voltage or breakdown voltage in an integrated circuit consists in using a reverse-biased PN junction. The breakdown voltage or avalanche voltage is then essentially set by the doping level of the less heavily doped region. For the PR junction, and especially for the less heavily doped region, it is desired to use a region having a doing level existing in the manufacturing technology of the integrated circuit where this PN junction is to be inserted, to avoid having to use a specific technological step to manufacture the avalanche diode. It is thus not always possible to directly obtain the desired breakdown voltage.
The same issue arises all the more when several avalanche diodes are desired to be formed in an integrated circuit, such avalanche diodes having different determined breakdown voltages. The number of breakdown voltages which can be obtained is rather limited and such voltages are predetermined by the doping levels existing in the various integrated circuit manufacturing blocks.
There thus is a need, especially in the field of integrated circuits, for avalanche diodes having adjustable avalanche voltages without requiring the use of specific doping levels or of complex structures.